The United States and Japan will step up their defence cooperation to deal with the threat from nuclear-armed North Korea as tensions in East Asia remain high, officials from the two allies said on Thursday.

Trade, labour on B20 business wish list

Business leaders have told the world's governments they want trade barriers slashed, more flexible labour markets and help to invest in new infrastructure.

The B20 summit of business leaders has wrapped up in Sydney with the presentation of 20 recommendations they say could, if enacted, add $2 trillion to global gross domestic product and create millions of jobs within five years.

New private sector infrastructure investment was a major focus, with business urging governments to create lists of bankable projects overseen by independent authorities.

Free trade, an end to protectionist policies, more business-friendly banking regulations and labour market deregulation were also key themes.

Federal treasurer Joe Hockey told the 400 delegates that governments worldwide had "run out of money" and could not build vital infrastructure needed by their populations.

"We need you and we need your money," he said.

B20 chairman and Wesfarmers chief executive Richard Goyder said governments had to make structural reforms to encourage businesses to start investing after years of stagnation since the 2008 global financial crisis.

"We are asking governments to remove barriers and impediments to growth."

The two-day summit attracted world business leaders including News Corporation executive chairman Rupert Murdoch, who said governments should "take a back seat" and let free markets create wealth.

However, Mr Hockey called on business to become "preachers" to build public support for governments making unpopular decisions, such as ending support for the Australian car industry and selling off public assets.

BHP Billiton chief executive Andrew Mackenzie, who chaired the B20 trade taskforce, said governments had to "energise" the private sector.

Measures to boost free trade, including implementation of the 2013 Bali Trade Facilitation Agreement and winding back of non-tariff barriers, were high on the list.

Business also called for structural reforms in labour markets to boost flexibility and make cross-border movements easier.

Advocates denied that would mean lower wages or lessened conditions in developed nations such as Australia.

G20 nations were also urged to reform their domestic supply chains to make trade easier, and use imported materials rather than more expensive locally produced inputs as part of an efficiency-boosting "made in the world" approach to manufacturing.

Telstra chief David Thodey, who chaired the infrastructure taskforce, said $1 trillion worth of roads, hospitals, ports and other vital works was unfunded every year.

The business group made no recommendations on corporate taxation - a key issue for governments dealing with companies sending profits offshore to lower-taxing regimes.

Mr Goyder said business recognised it was a serious issue but "it's unrealistic to expect business to solve an issue which absolutely goes to governments' own fiscal policies", he said.

The B20 recommendations were presented to Mr Hockey on Friday ahead of the G20 meeting of government leaders in Brisbane in November.